Micro-mixing combustion is a kind of potential technology to reduce pollutant emissions, and the microtube structure as a basic unit has significant influence on combustion characteristics. Taking the single microtube model burner as the object, the computational fluid dynamics (CFD) method is employed to analyze methane micro-mixing combustion characteristics with different microtube diameters, rear-section lengths, and chamber-to-tube area ratios, under the air-preheated and pressurized condition and the atmospheric condition. The numerical simulation results show that, the flame length increases obviously under the atmospheric condition, and the increase rate is greatly affected by the microtube diameter and the area ratio. With the increase of microtube diameter, the flow and temperature fields in the flame chamber are similar, and the dimensionless flame length does not change significantly. However, when the microtube diameter is smaller, the change of flame length is smaller between two working conditions, and the flexibility is better. With the increase of microtube rear-section length, the turbulence intensity at the microtube outlet reduces greatly, and the flame length increases obviously, but the change trend of flame length is consistent under two working conditions. With the increase of chamber-to-tube area ratio, the flame length decreases at first and then increases. When the area ratio is 4.0~9.0, the flame length is relatively short, and the combustion performance is relatively good. The results have reference value for the gas turbine combustor, and also have certain reference significance for free jet flame.

With the proposal of "carbon peaking and carbon neutral", the total installed capacity of renewable energy power units continues to increase. This may greatly challenge the safety and stability of power grid. The characteristics of flywheel energy storage system (FESS) are fast response, unlimited times of charge and discharge and deep depth of discharge. FESS has been widely used in frequency modulation and frequency safety improvement of power grid. In order to make full use of the advantage of flywheel energy storage in auxiliary frequency modulation of the power grid, an adaptive coordinated droop control strategy of primary frequency regulation coordinated with thermal power units was designed, which realized the power cooperative adaptive adjustment of the combined coal-fired thermal power units and storage systems. Simulation results show that, the proposed control strategy can effectively improve the frequency modulation performance of the combined fire-storage system. Compared with the conventional droop control, the maximum dynamic frequency difference and steady frequency difference of the system reduces by 29.00% and 25.50% respectively, which eases the frequency modulation pressure of thermal power unit, and is benefit to safety and stability of the thermal power unit.

In order to improve the energy utilization efficiency of high flexibility power generation system coupled with internal combustion engine and coal-fired unit, a new thermal system combined with the internal combustion engine and the coal-fired unit was proposed. By feeding the flue gas of internal combustion engine and the waste heat of cooling water into the thermal system of coal-fired generating unit, the coal consumption of coal-fired generating unit can be reduced. EBSILON software was used to model the composite system. Steam consumption rate and heat consumption rate of the coal-fired units were taken as evaluation indexes to analyze the thermal economy of the coal-fired unit under different composite schemes. The results show that, the heat consumption rate and steam consumption rate of the coal-fired unit can be significantly reduced by combining the waste heat of the internal combustion engine into the thermal system of the coal-fired unit. The closer the compound position of flue gas waste heat is to the boiler, the smaller the proportion of feed water and condensed water involved in flue gas heat exchange, and the lower the heat consumption rate and steam consumption rate of the unit. When one part of the flue gas waste heat is used to heat the high pressure heater feed water and the other part is used to heat the low pressure heater condensed water, more waste heat will be allocated to feed water, and the heat consumption rate and steam consumption rate of the unit wil decrease. After optimization, the heat consumption rate of the combustion engine and coal-fired unit combined thermal system can be reduced by 6.62% at most.

An efficient integrated power generation system of solid waste coupled with anaerobic fermentation and incineration is proposed. Solid waste anaerobic fermentation is adopted to generate biogas, which enters the biogas burner to burn and generates high-temperature flue gas, and the flue gas heats the steam-water system and the primary and secondary air through the heater and air preheater in the unit. Under the condition that the heat generated by solid waste incineration in the boiler is not changed, the energy entering the steam turbine to do work is increased, thus the power generation efficiency of the whole unit increases. At the same time, according to the first law of thermodynamics and the second law of thermodynamics, the reasons for power generation efficiency and exergy efficiency improvement are analyzed. The results show that, compared with the case unit, the proposed high-temperature flue gas system with biogas combustion can increase the net power generation by 8.69 MW. In addition, the power generation efficiency and power generation exergy efficiency of the new system has increased by 3.56 percentage points and 9.74 percentage points, respectively. Economic analysis shows that the proposed coupling system is equipped with an anaerobic fermentation biogas combustion system, and the dynamic recovery period is 3.78 years, which has obvious economic advantages.

The variable operating condition of thermal power units makes the data show multi-modal characteristics, which leads to the decrease of prediction accuracy of the regression soft sensor model based on shallow network structure. An improved BP neural network (back propagation neural network, BPNN) soft sensor method is studied. Firstly, the original data features are extracted by using the strong deep learning ability of stacked sparse autoencoder (SSAE), and then the extracted features are analyzed by BPNN. The experimental results show that, the mean square error of the SSAE+BPNN soft sensor method is 0.135 8×10^–3 and the square correlation coefficient is 0.983 2. It is proved that its prediction accuracy and generalization ability are significantly better than those of BPNN. It is applied to the soft sensor of carbon content in fly ash of a flexible peak-shaving 660 MW ultra-supercritical generator set, and the average relative error of the prediction results is 0.91%, the overall relative error is less than±5%, indicating the method has good engineering application value.

By taking a supercritical 600 MW opposed firing boiler as the research object, the temperature deviation law of main steam on both sides is analyzed and verified through hydrodynamic modeling, and a technical scheme is put forward to optimize the temperature deviation of main steam from the perspective of water side. After adopting this steam temperature optimization scheme, the main steam temperature deviations on both sides of the boiler reduced by 44.6%, 95.8% and 28.0% respectively under 50%, 75% and 100% BRL conditions. This scheme can realize safe and economical operation of the unit, and has good guidance and reference value for the same type of boiler.

With high power generation efficiency and low carbon emission, (ultra) supercritical unit is the main type in China's development of thermal power units. Optimization on feed water operating condition of the (ultra) supercritical unit is of great guiding significance. The optimal control indexes of different feed water operating conditions of (ultra) supercritical units are investigated by in-situ sampling test, and the influence of centralized sampling on feed water quality is researched. Moreover, the intelligent control system for feed water operating condition is developed. The results show that, the optimal target value of feed water conductivity is 6.7 μS/cm under AVT(O) condition, the optimal target value of feed water dissolved oxygen is 15 μg/L and the optimal target value of feed water conductivity is 3.0 μS/cm under OT condition. Long sampling pipeline of feed water will cause the deposition of iron corrosion products, and interfere with the judgment of unit corrosion. The chromates produced by adding oxygen to feed water is only related to the oxidation of the sampling tube and has nothing to do with the water vapor system.

In the point cloud splicing of underground pipe gallery in power plants, an improved algorithm with 3D-Harris operator about corner detection is proposed. In this algorithm, firstly, taking multiple sets of massive point cloud data of the underground pipe gallery as analysis object, the normal information of the target detection point on the adjacent point cloud microtangent plane is obtained through principal component analysis method, thus the boundary points of the point cloud are extracted. Secondly, the covariance matrix is constructed according to the normal information of the target detection point, then the corner response intensity function is calculated and compared, and some points are selected as calculation objects to judge whether they are true corner. Thirdly, the pseudo angles are filtered out and the true angles are selected by using a pseudoangle detection method based on Gaussian curvature extreme points. At last, the fast point feature histogram method is used to match similar corners between each group, and the nearest point search point cloud registration algorithm is used to realize the splicing of multiple points and cloud in the underground pipe gallery. The results are compared with that of the conventional 3D-Harris angular point detection algorithm. It is proved that the method in paper takes less time to calculate and has a higher corner-point extraction accuracy, which can realize accurate splicing of massive point cloud of underground pipe gallery.

The high-temperature and high-pressure (300 ℃/10 MPa) corrosion electrochemical behavior and oxide film microscopic features of Incoloy 800H alloy aged at 675 ℃ for 0~10 000 h in alkaline environament were investigated systematically. By means of electrochemical test, long-term immersion test, scanning electron microscope/transmission electron microscope observation, Raman spectroscopy/fast Fourier transform analysis and other methods, the electrochemical activity, evolution of oxide film morphology and composition characteristics of the 800H alloy with extension of aging time were systematically studied. The results show that, the value of open circuit potential and self-corrosion potential E_corr of the 800H alloy in high-temperature and high-pressure water can be slightly increased by aging treatment, but the effect of aging time extension on the electrochemical behavior was not significant. A passive to trans-passive process was depicted. The oxide film of the 800H alloy formed in high-temperature and high-pressure water had a multilayer structure: the most outer layer was the dispersed large particle oxides composed of Fe₂O₃ or NiFe₂O₄; the middle layer was relatively compact small size oxides, mostly NiFe₂O₄ or FeCr₂O₄; while the inner layer was dense and continuous oxides, amorphous or nanocrystalline oxide containing Cr and a small amount of Fe. The 800H alloy has good corrosion resistance and surface stability in alkaline high temperature and high pressure water of 300 ℃/10 MPa.

In order to select high activity catalysts for urea hydrolysis, the kinetic and thermodynamic characteristics of urea catalytic hydrolysis reaction were studied by using batch reactor and continuous operation pilot plant, and the effects of different catalysts on hydrolysis reaction temperature, energy consumption and variable load response time were compared. The results show that, the activation energy of the hydrolysis reaction can be reduced by adding catalyst (the activation energy of the liquid diammonium hydrogen phosphate is 65.3 kJ/mol, and that of the solid alumina is 52.9 kJ/mol), and the urea conversion can be improved. The addition of catalyst increases the hydrolysis reaction rate and decreases the hydrolysis reaction temperature. Due to uneven distribution and insufficient contact, the catalytic activity of solid alumina catalyst decreases in the continuous operation reactor. The energy consumption of ammonia production by catalytic hydrolysis is about 1%~3% lower than that of ordinary hydrolysis, and the response time of hydrolyzer changing load is not shortened by adding diammonium phosphate and alumina catalyst.